In the binding of magazines, pamphlets and the like the folded sheets or signatures of the magazine are assembled or gathered one atop another on a saddle conveyor and then passed under a stitching machine in an open face-down relation. See U.S. Pat. Nos. 3,275,210 and 3,542,271. The stitching machine supports a plurality of stitcher heads, shown for example, in U.S. Pat. Nos. 3,876,129 and 3,664,655, each of the stitcher heads being adapted to cut and shape a wire staple and to drive that staple through the magazine to thereby bind the pages of the magazine together. In conventional full size magazines, the stitcher machine employs two or three spaced apart stitcher heads so that each magazine has two or three staples binding it. If smaller magazines are to be bound, the stitcher heads are moved closer together.
Many of the stitching machines presently in common use are described as model 18D stitcher machines and are produced by manufacturers such as McCain Manufacturing Corporation of Chicago, Ill. Such stitching machines employ relatively large stitcher heads, also commonly referred to in the industry as 18D stitcher heads. Such stitcher heads are shown for example by those manufactured by Bostich Corp., Indianapolis, Indiana. While the 18D stitcher heads are advantageous in that they are constructed so as to be particularly durable, long wearing and capable of high speed operation, these advantages are achieved by making the stitcher heads relatively large and of substantial width. The width of the 18D stitcher heads is such that while several staples can be driven through a magazine of a conventional 11 inch height, if the magazine is relatively small, only two staples can be driven into the magazine. In some applications, this is insufficient to properly bind the magazine or pamphlet.
Prior to development of the 18D stitching machines and 18D stitcher heads, stitching machines commonly employed a smaller, substantially narrower stitcher head referred to as a 26D stitcher head, such stitcher heads being produced, for example, by Bostich Corp., Indianapolis, Indiana.
As stated, the stitcher head receives a single strand of wire from a spool and feeds, cuts, and shapes the wire to form a staple and then drives the staple through the open face-down signature. The construction of the 26D stitcher head is such that it includes a single member driven by the stitching machine, the single driven member effecting feeding, cutting, and shaping of the wire and driving of the staple. In order to improve the durability and speed of operation of the stitcher heads, the design of the 18D stitcher head employs two reciprocably driven members rather than a single reciprocably driven member, and the 18D stitching machine includes a first reciprocably driven driver for causing reciprocation of one of the driven members and a second reciprocably driven member for causing reciprocation of the other of the driven members.
While it would be desirable to employ the smaller, narrower 26D stitcher when smaller signatures are to be bound, since they can be positioned in more closely adjacent relation, the 26D stitcher head cannot be employed on an 18D stitcher machine because the 26D stitcher head cannot be fixedly mounted on an 18D machine and the two drive bars of the 18D machine are not adapted to drive the driving member of the 26D stitcher head.